1. Field of the Invention.
My invention relates to methods and apparatus for the protection and control of computer programs, and more particularly to non-cryptographic methods and apparatus for the protection and control of computer programs.
2. Description of the Prior Art.
The term "prior art" as used herein or in any statement made by or for applicant means only that any document or thing referred to as prior art bears or might be contended to bear, directly or inferentially, a date which is earlier than the effective filing date hereof. It is believed that the documents listed immediately below contain information which is or might be considered to be material to the examination of this patent application, since they were discovered by two independently made preliminary patentability searches.
U.S. Pat. No. 3,798,359 PA1 U.S. Pat. No. 3,906,460 PA1 U.S. Pat. No. 3,909,795 PA1 U.S. Pat. No. 3,911,216 PA1 U.S. Pat. No. 3,958,081 PA1 U.S. Pat. No. 3,978,454 PA1 U.S. Pat. No. 4,038,596 PA1 U.S. Pat. No. 4,070,702 PA1 U.S. Pat. No. 4,107,458 PA1 U.S. Pat. No. 4,120,030 PA1 U.S. Pat. No. 4,122,519 PA1 U.S. Pat. No. 4,157,454 PA1 U.S. Pat. No. 4,158,396 PA1 U.S. Pat. No. 4,188,789 PA1 U.S. Pat. No. 4,278,037.
No representation is made herein that no more pertinent information exists.
Methods and apparatus for the protection and control of computer programs are to be found in the prior art.
Many of the prior art methods and apparatus for the protection and control of computer programs are cryptographic in character, relying upon the encryption of the programs to be protected or controlled or parts thereof, and thus necessitating the incorporation of decrypting means, i.e., special circuits and/or programs and data, into each computer in which such an encrypted program is to be run.
Thus, even the simplest of these prior art cryptographic systems involve considerable cost, both for the encryption of the programs and for the modification of the associated computers to decrypt the encrypted programs. Further, the encryption and decryption of the programs of these systems necessarily produces additional possibilities of error and difficulties in the servicing of the computers thereof.
Non-cryptographic arrangements for the protection of computer-controlled communications and industrial processing equipment against erroneous modifications of their control programs are also known in the prior art, but the operating principles of these arrangements are either inapplicable to general purpose digital computers and their programs or do not appear to have been applied thereto.